Are Legionella Regulations Raising the Bar?

Patrick Racine, P.Eng.

Author: Patrick Racine | Vice President - Sales

Raising the Bar - Pole Vaulter

Localized Legionella regulations often get implemented following an outbreak.  Many questions have been raised regarding the effectiveness of such regulations.  Eldon Water used the power of our AquaAnalytics data management platform to attempt to answer these questions.  This blog reviews some of our preliminary conclusions regarding the impact of such regulations on the incidence and level of Legionella in cooling towers.  Further analysis and conclusions will be presented in Baltimore at the Legionella Conference 2018 (#LEGIONELLA2018organized by NSF International with the support from the National Science Foundation and participation from U.S. EPA and Centers for Disease Control and Prevention (CDC).

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Cooling Tower Regulations and Peace of Mind

Legionella risk mitigation measures have received more press coverage over the last few years.  Some may question if this is just white noise.  Data from the Centers for Disease Control and Prevention shows the incidence rate has quadrupled in the last 15 years.

A Need for Action

Legionella outbreaks in various North American geographies have resulted in localized legislation and regulations.  Following the Quebec City Legionella outbreak in 2012, the province of Quebec introduced legislation requiring owners of evaporative cooling systems to register their cooling towers.  Owners must now document the mechanical maintenance program as well as their water treatment program.  Since July 2014, the regulation also required Legionella sampling of cooling towers on a 30-day interval basis.

Four Years later, is this having a positive impact?

Though we observed a large pushback across the industry, these regulatory changes offered an opportunity to collect a significant amount of data on cooling water programs and the presence of Legionella bacteria in cooling systems.  Over 10,000 Legionella samples were collected in the province during the four years and logged in our cloud based AquaAnalytics platform.  As shown in the graph below, a strong improvement trend appeared from the onset of the sampling mandate.  At a glance, this indicated to us that the regulatory changes were having a positive impact on field results.  These strong improvements in results were achieved without changing the water treatment programs, but rather by raising awareness and accountability.

Quebec Legionella Results 2014-2017

"You can’t manage what you don’t measure" - Peter Drucker

Our observations through the last four years indicate that measuring the performance of the water treatment program through Legionella sampling, created a willingness to improve these programs.  Drawing on lessons from organizational behavior, regulations can have an impact on behavior through applying the 5 A’s:

  1. Assessment
  2. Awareness
  3. Accountability
  4. Action
  5. Acknowledgement

The Quebec regulation forced assessment through legislated sampling requirements.  This created a sense of awareness, and accountability from the cooling tower owners.  Actions were followed through and the impact of these actions were acknowledged through re-sampling.

So, What Changed?

The high level indication of improvement in results prompted us to do a deeper dive.  We next looked at the Legionella results in combination with all other measured water treatment parameters by our field engineers and chemists in our AquaAnalytics platform.  This is the largest known dataset of field collected cooling water treatment control results in over 300 evaporative cooling systems, combined with more than 10,000 corresponding Legionella culture results in North America.  This metadata analysis has allowed us to draw conclusions on the best practices related to Legionella control.  We are excited to be able to present these results in Baltimore at the Legionella Conference 2018 (#LEGIONELLA2018) organized by NSF International with the support from the National Science Foundation and participation from U.S. EPA and Centers for Disease Control and Prevention (CDC).

Now What?

The HVAC industry, including water treatment firms and cooling equipment manufacturers, are often reticent to the introduction of new regulations.  Our data indicates that regulations can raise the bar on how to properly control water treatment programs, leading to reduction in levels and incidences of Legionella positivity.  Clear and simple regulations can therefore have a major impact on the risk associated with the presence of higher levels of Legionella in cooling water systems.


Further analysis of this rich dataset is required to solidify our understanding of the leading indicators of higher Legionella results in the months prior to an incidence.  In the interim, the data confirms our strongly held belief that “You can’t manage what you don’t measure” and that following the 5 A’s not only has a positive impact on operating costs, but can also reduce risk by reducing the level and presence of Legionella in a cooling system.

Spring is the perfect time to also remind ourselves of the best practices for a cooling tower preventative maintenance program.  Following these best practices are equally important to both allow your cooling system to reach Least Cost Operating Solution, and to simultaneously minimize your Legionella risk.  If your cooling system was idle for the winter months, reviewing the 5 Simple Steps for cooling tower startups would also be timely.

Download Eldon Water’s Checklist of Best Practices for Minimizing Legionella Risk for Evaporative Cooling Systems

Patrick Racine, P.Eng.

Patrick Racine has a Mechanical Engineering degree from McGill University. As Vice President – Sales, Patrick is responsible for overseeing operation of all districts and ensuring overall customer satisfaction. He is a recognized public speaker on topics of controls, pre-treatment solutions and Legionella prevention. Patrick has a passion for open water swimming and has swam Lake Michigan, Lake Ontario and many inland lakes in Michigan, Indiana, Ontario and Quebec. His goal is to swim in all 5 Great Lakes and an ocean swim.

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